EP0241362B1 - Vorrichtung, insbesondere Duoplasmatron, zur Ionisierung eines Gases und Verfahren zur Benutzung dieser Vorrichtung - Google Patents

Vorrichtung, insbesondere Duoplasmatron, zur Ionisierung eines Gases und Verfahren zur Benutzung dieser Vorrichtung Download PDF

Info

Publication number
EP0241362B1
EP0241362B1 EP87400738A EP87400738A EP0241362B1 EP 0241362 B1 EP0241362 B1 EP 0241362B1 EP 87400738 A EP87400738 A EP 87400738A EP 87400738 A EP87400738 A EP 87400738A EP 0241362 B1 EP0241362 B1 EP 0241362B1
Authority
EP
European Patent Office
Prior art keywords
cathode
electrodes
gas
filament
anode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87400738A
Other languages
English (en)
French (fr)
Other versions
EP0241362A1 (de
Inventor
Bruno Blanchard
Pierre Juliet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP0241362A1 publication Critical patent/EP0241362A1/de
Application granted granted Critical
Publication of EP0241362B1 publication Critical patent/EP0241362B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J27/00—Ion beam tubes
    • H01J27/02—Ion sources; Ion guns
    • H01J27/022—Details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J27/00—Ion beam tubes
    • H01J27/02—Ion sources; Ion guns
    • H01J27/08—Ion sources; Ion guns using arc discharge
    • H01J27/10—Duoplasmatrons ; Duopigatrons

Definitions

  • the present invention relates to a device usable for ionizing a gas and comprising a cathode serving as a hot or cold cathode and a method of using this device.
  • the invention applies to all devices used in particular for ionizing a gas such as electric arcs, unoplasmatrons and duoplamatrons.
  • a gas such as electric arcs, unoplasmatrons and duoplamatrons.
  • the invention will be described from a duoplasmatron used for example in surface analysis apparatus as an ion source for abrading samples.
  • a duoplasmatron comprises either a cold cathode or a hot cathode.
  • Figure 1 shows schematically in longitudinal section a duoplasmatron with cold cathode of known type.
  • This duoplasmatron comprises a hollow cathode 1 of cylindrical shape, the upper part of which is mounted on a generally conductive support 2, an intermediate electrode 3 surrounding the cathode 1 and comprising in its lower part an opening 4 and an anode 5 surrounding the intermediate electrode 3 , provided opposite the opening 4 of this electrode, with an opening 6 of divergent shape towards the outside.
  • the cathode 1 is made of nickel and the intermediate electrode 3 and the anode 5 are made of soft iron.
  • the cathode 1 mounted on the support 2, the intermediate electrode 3 and the anode 5 are electrically isolated. These three elements are arranged one inside the other so as to define three chambers 11, 13, 15 communicating with each other, seals 8, 9 ensuring the tightness of these chambers with the outside.
  • the chamber 11 is defined by the internal cylindrical walls of the cathode, the chamber 13 by the space provided between the cathode 1 and the intermediate electrode 3 and the chamber 15 by the space defined between the intermediate electrode 3 and the anode 5.
  • a magnetic coil 21 surrounds the chambers 11, 13, 15; this coil is located around the upper part of the anode 5 and rests on both the lower part of the anode 5 and the upper part of the intermediate electrode 3.
  • a voltage generator 23 connected for example to the lower part of the anode 5 and to the conductive support 2 of the cathode 1 makes it possible to apply a potential difference Va-Vc of the order of 300 to 500 volts between the anode and the cathode, Va represents the voltage applied to the anode and Vc the voltage applied to the cathode.
  • This voltage Vi can also be obtained from the voltage generator 23 via a divider bridge connected to the intermediate electrode and to the voltage generator 23. In this case, the generator 25 is omitted.
  • Means for making the vacuum ensure the evacuation for example by the opening 6 of any gas present in the chambers 11, 13 and 15 before the introduction of the gas to be ionized into the duoplasmatron .
  • the gas to be ionized is stored for example in a bottle 16 connected by a pipe 17 to the support 2 of the cathode 1, said support comprising a passage 10 connected to the chamber 11. Opening and closing means such as a valve 17 ′ arranged for example on the pipe 17, makes it possible to introduce a regulated flow of gas into the duoplasmatron, from the bottle 16.
  • gas is introduced into the duoplasmatron by opening the valve 17 '.
  • the gas will circulate in the chamber 11 where it will be ionized by the electrons emitted by the cathode 1 on which the potential Vc is applied.
  • a plasma of ions and electrons is then formed which will be entrained towards the intermediate electrode 3, by the electric field 1 induced by the potential difference Vi-Vc between the cathode 1 and the electrode 3.
  • This plasma will pass through the opening 4 driven by an electric field 2 induced by the potential difference Va-Vi between the electrode 3 and the anode 5 as well as by a magnetic field between the electrode 3 and the anode 5.
  • This field circulates in a closed loop between the magnetic coil 21, the intermediate electrode 3 on which the coil rests, the part of the chamber 15 defined between the lower part of the intermediate electrode 3 and the upper part of the anode 5 and finally the anode 5 on which also rests the magnetic coil.
  • the plasma is therefore confined by the electric field 2 and the magnetic field between the intermediate electrode 3 and the anode 5. This plasma then passes through the opening 6 formed in the anode 5, driven by an electric field 3 induced by the potential difference between the anode and the surface 20 to be abraded generally to ground.
  • this duoplasmatron To operate as a hot cathode, this duoplasmatron must be dismantled to replace the cylindrical cathode 1 by a filament wound in a helix following a cylinder whose axis is perpendicular to the direction of the gas flow.
  • This filament is connected by each of its ends to a separate conductive tab mounted on the support 2, the gas to be ionized passing between these tabs and through the filament.
  • voltages Vc, Va and Vi are applied respectively to the support 2, to the anode 5 and to the intermediate electrode 3. Furthermore, a voltage Vs is applied between the two ends of the filament by a voltage generator; this voltage Vs allows the circulation of a current in the filament and consequently the heating of the filament by Joule effect.
  • the electronic emission is produced in particular by the bombardment of this one by the ions and electrons of the plasma; this emission therefore depends on the conditions prevailing in the duoplasmatron such as pressure, electric fields and the nature of the gas.
  • the electronic emission of a hot cathode due to the heating of the filament, is determined in particular by its temperature and therefore by the intensity of the current 1 which it is easy to regulate.
  • the hot cathode therefore allows a more stable electronic emission, the intensity of which can generally be adjusted greater than that provided by a cold cathode. Therefore, in operation in hot cathode, a potential difference Va-Vc of the order of a few tens of volts is sufficient.
  • a cold cathode or a hot cathode is used with reactive gases such as oxygen which would attack a filament (hot cathode), on the other hand, for inert gases such as argon, xenon, etc., it is more advantageous to use a hot cathode.
  • the hot cathode allows operation of the duoplasmatron with a lower pressure of the order of 10- 4 Pa and gives, because the electronic emission serving to ionize the gas is more stable, better stability of the current. ions extracted.
  • duoplasmatron With a duoplasmatron of known type, to pass from an operation in hot cathode to an operation in cold cathode, it is necessary to disassemble the duoplasmatron, which means in particular the stop of the use of the duoplasmatron and the rupture of the vacuum.
  • the object of the present invention is precisely to remedy these drawbacks by providing a device which can be used to ionize a gas operating as a cold cathode or a hot cathode without dismantling the device.
  • the invention relates to a device usable for ionizing a gas comprising a cathode and an opposite anode, the gas to be ionized successively passing through the cathode and the anode, characterized in that the cathode is formed of a first and a second facing electrodes, the gas to be ionized passing between said electrodes and a conductive filament connected by a first end to the first electrode and by a second end to the second electrode and located between said electrodes.
  • the first and second electrodes are half-cylinders arranged opposite so as to form a split cylinder according to two opposite generatrices and the filament is connected to the outlet ends of the gas to be ionized from the first and second electrodes.
  • the filament is wound in a helix along a cone, the axis of which coincides with the longitudinal axis of the cylinder created by the first and second electrodes, the gas to be ionized passing through this cone from its top.
  • This cone has an angle at the top ranging for example from 7 to 15 °.
  • the first and second electrodes are made of titanium and the filament is of tantalum.
  • the invention also relates to a duoplasmatron comprising a device as described above.
  • the invention also relates to a method of using the device which can be used to ionize a gas, this method is characterized in that this device operating as a cold cathode, a potential difference is applied between the anode and the first and second electrodes .
  • a first potential difference is applied between the anode and the first and second electrodes, and a second potential difference is applied between the first and second ends of the filament.
  • the cathode 30 shown in FIG. 2 is made up of two opposite electrodes 31, 33 and a conductive filament 35 connected by one of its ends 32 to the electrode 31 and by its other end 34 to the electrode 33.
  • the two electrodes 31 and 33 are respectively constituted by a half-cylinder opposite one another so as to form a split cylinder according to two opposite generatrices, the gas to be ionized passing through this cylinder.
  • This cylinder has for example a diameter of 40 mm and a length of 70 mm.
  • the filament 35 is wound in a helix (see FIG. 3) along a cone with an angle at the apex comprised between values of the order of 7 to 15 ° and a length for example of 15 mm. This filament is located at the gas outlet ends of the first and second electrodes and it is traversed by the gas from the top of the cone that it forms.
  • the two electrodes are preferably made of titanium.
  • titanium makes it possible to obtain a purer ion beam than the nickel used in the prior art.
  • the filament is advantageously in tantalum, the latter having a lifetime of 5 to 10 times longer than that of a tungsten filament used under the same conditions.
  • the wear of the filament is essentially due to sputtering, or the sputtering of tungsten is greater than that of tantalum.
  • the resistivity of tantalum being greater than that of tungsten, a filament with a diameter of approximately 0.7 mm is used instead of 0.5 mm for a tungsten filament of the prior art.
  • the axis of the cone formed by the filament coincides with the longitudinal axis of the cylinder created by the two electrodes 31, 33; this particular arrangement also makes it possible to increase the life of the filament by a factor of the order of 4 to 5.
  • the lifetime of the filament exceeds one month.
  • a voltage generator 37 and a switch 39 in series are connected between the two ends of the filament.
  • this cathode 30 in a duoplasmatron, it is mounted on the support 2 of FIG. 1 in place of the cathode 1.
  • the lower part of the electrodes 31 and 33 being connected to the filament 35.
  • the first and second electrodes and the support are preferably made in a single piece but of course the first and second electrodes can also be attached to the support.
  • This support is also advantageously made of titanium.
  • a potential difference Va-Vc is applied between the electrodes 31 and 33 and the anode 5 by the voltage generator 23 and a voltage Vi is applied as previously to the intermediate electrode 3.
  • the duoplasmatron When the switch 39 is closed, a voltage Vs is applied to the ends of the filament by the generator 37.
  • Vs a voltage applied to the ends of the filament by the generator 37.
  • the duoplasmatron operates as a hot cathode. Indeed, the filament traversed by a current gives off heat by the Joule effect. This filament then emits electrons which will ionize gas atoms. The ions formed will be confined as described above in electric and magnetic fields before being extracted from the duoplasmatron.
  • the potential difference Va-Vc applied between the first and second electrodes and the anode is of the order of a few tens of volts, the voltage Vs applied between the two ends of the filament is of the order of some 0.1 volts and the current flowing in the filament is of the order of a few amperes.
  • the electrons are mainly emitted by the filament.
  • the quantity of electrons emitted by the first and second electrodes is very small due to the small potential difference Va-Vc.
  • the duoplasmatron When the switch 39 is open, the voltage applied to the filament 35 is zero, no current flows in the filament: the duoplasmatron operates as a cold cathode. In this case, so that the first and second electrodes emit enough electrons to ionize the gas, a different potential Va-Vc of the order of 300 to 500 volts is applied between the anode and the first and second electrodes .
  • cathode according to the invention serving as a cold cathode or a hot cathode in a duoplasmatron, but of course, the invention applies to all ion sources using a cold or hot cathode .

Claims (9)

1. Vorrichtung, die zum lonisieren eines Gases verwendbar ist, mit einer Kathode (30) und einer gegenüberliegenden Anode (5), wobei das zu ionisierende Gas nacheinander die Kathode und die Anode passiert, dadurch gekennzeichnet, daß die Kathode (30) aus einer ersten und einer zweiten Elektrode (31, 33), die Halbzylinder sind, die einander gegenüberliegend derart angeordnet sind, daß sie einen entlang zweier seiner gegenüberliegenden Erzeugenden gespaltenen Zylinder bilden, wobei das zu ionisierende Gas zwischen den Elektroden entlang einer im wesentlichen zur Zylinderachse parallelen Richtung hindurchgeht, und einem Leiterdraht (35) besteht, der an einem ersten Ende (32) mit der ersten Elektrode (31) und an einem zweiten Ende (34) mit der zweiten Elektrode (33) verbunden ist und sich zwischen den Elektroden befindet, und dadurch, daß die Vorrichtung umfaßt:
- eine erste Spannungsquelle (23), die auf der einen Seite mit der Anode (5) verbunden ist und auf der anderen Seite mit der ersten und zweiten Elektrode (31, 33) der Kathode (30) verbunden ist;
- eine zweite Spannungsquelle (37), die über einen Schalter (39) mit der ersten und zweiten Elektrode (31, 33) verbunden ist.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der Draht (35) mit den Enden am Ausgang des zu ionisierenden Gases der ersten und zweiten Elektrode (31, 33) verbunden ist.
3. Vorrichtung nach einem der Ansprüche 1 bis 2, dadurch gekennzeichnet, daß der Draht (35) in Schraubenform entlang eines Kegels aufgewickelt ist, dessen Achse mit der Achse des Zylinders zusammenfällt, wobei das zu ionisierende Gas diesen Kegel von seiner Spitze aus durchquert.
4. Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß der Kegel einen Winkel an seiner Spitze besitzt, der zwischen 7 und 15 ° liegt.
5. Vorrichtung nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die erste und zweite Elektrode (31, 33) aus Titan bestehen.
6. Vorrichtung nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß der Draht (35) aus Tantal besteht.
7. Duoplasmatron, dadurch gekennzeichnet, daß es eine Vorrichtung nach einem der Ansprüche 1 bis 6 umfaßt.
8. Verfahren zur Verwendung der Vorrichtung, die zum lonisieren eines Gases verwendbar ist, nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß, während die Vorrichtung mit kalter Kathode arbeitet, eine Spannungsdifferenz zwischen der Anode (5) auf der einen Seite und der ersten und zweiten Elektrode (31, 33) auf der anderen Seite angelegt wird.
9. Verfahren zur Verwendung der Vorrichtung, die zum lonisieren eines Gases verwendbar ist, nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß, während die Vorrichtung mit warmer Kathode arbeitet, eine erste Spannungsdifferenz zwischen der Anode (5) auf der einen Seite und der ersten und zweiten Elektrode (31, 33) auf der anderen Seite und eine zweite Spannungsdifferenz zwischen dem ersten und dem zweiten Ende des Drahtes (32, 34) angelegt wird.
EP87400738A 1986-04-09 1987-04-03 Vorrichtung, insbesondere Duoplasmatron, zur Ionisierung eines Gases und Verfahren zur Benutzung dieser Vorrichtung Expired - Lifetime EP0241362B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8605064A FR2597286B1 (fr) 1986-04-09 1986-04-09 Dispositif et notamment duoplasmatron utilisable pour ioniser un gaz comprenant une cathode servant de cathode chaude ou froide et procede d'utilisation de ce dispositif
FR8605064 1986-04-09

Publications (2)

Publication Number Publication Date
EP0241362A1 EP0241362A1 (de) 1987-10-14
EP0241362B1 true EP0241362B1 (de) 1992-07-29

Family

ID=9334059

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87400738A Expired - Lifetime EP0241362B1 (de) 1986-04-09 1987-04-03 Vorrichtung, insbesondere Duoplasmatron, zur Ionisierung eines Gases und Verfahren zur Benutzung dieser Vorrichtung

Country Status (4)

Country Link
US (1) US4752667A (de)
EP (1) EP0241362B1 (de)
DE (1) DE3780675T2 (de)
FR (1) FR2597286B1 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5257500A (en) * 1992-07-27 1993-11-02 General Electric Company Aircraft engine ignition system
DE102006027853B4 (de) * 2006-06-16 2012-06-14 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Verfahren und Vorrichtung zum Erzeugen eines Plasmas sowie Verwendung derselben
US7550741B2 (en) * 2006-10-18 2009-06-23 Sanns Jr Frank Inertial electrostatic confinement fusion
EP2716141B1 (de) 2011-05-23 2016-11-30 Schmor Particle Accelerator Consulting Inc. Teilchenbeschleuniger und verfahren zur reduzierung der strahldivergenz in dem teilchenbeschleuniger
US10134557B2 (en) 2013-06-12 2018-11-20 General Plasma, Inc. Linear anode layer slit ion source

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3164739A (en) * 1960-07-20 1965-01-05 Vakutronik Veb Ion source of a duo-plasmatron
US3513351A (en) * 1968-06-26 1970-05-19 Atomic Energy Commission Duoplasmatron-type ion source including a gas reservoir
GB1243483A (en) * 1969-06-12 1971-08-18 Hughes Aircraft Co An ion source
US3705998A (en) * 1972-01-27 1972-12-12 Us Army Negative ion generator
US4596945A (en) * 1984-05-14 1986-06-24 Hughes Aircraft Company Modulator switch with low voltage control
US4659899A (en) * 1984-10-24 1987-04-21 The Perkin-Elmer Corporation Vacuum-compatible air-cooled plasma device

Also Published As

Publication number Publication date
EP0241362A1 (de) 1987-10-14
FR2597286B1 (fr) 1988-06-10
DE3780675T2 (de) 1993-02-04
US4752667A (en) 1988-06-21
DE3780675D1 (de) 1992-09-03
FR2597286A1 (fr) 1987-10-16

Similar Documents

Publication Publication Date Title
EP0200651B1 (de) Dreielektrodenionenquelle mit einer einzigen Hochfrequenzionisationskammer und mit multipolarer magnetischer Umschliessung
EP1496727B1 (de) Plasmabeschleuniger mit geschlossener Elektronenbahn
EP3344873B1 (de) Gitter-ionenantrieb mit integriertem festtreibstoff
FR2501725A1 (fr) Procede et dispositif pour l'evaporation d'un materiau sous vide
FR2797372A1 (fr) Procede de production de plasmas elementaires en vue de creer un plasma uniforme pour une surface d'utilisation et dispositif de production d'un tel plasma
FR2887072A1 (fr) Systeme spectographique ameliore avec source plasma
FR2691834A1 (fr) Procédé pour produire et pour amorcer une décharge basse tension, installation de traitement sous vide et chambre à cathode pour celle-ci, et utilisations du procédé.
EP0238397A1 (de) Elektronenzyklotronresonanz-Ionenquelle mit koaxialer Injektion elektromagnetischer Wellen
EP0241362B1 (de) Vorrichtung, insbesondere Duoplasmatron, zur Ionisierung eines Gases und Verfahren zur Benutzung dieser Vorrichtung
EP2195643A1 (de) System zur analyse eines niederdruckgases mittels optischer emissionsspektroskopie
FR2660999A1 (fr) Manometre ameliore a ionisation pour pressions tres faibles.
WO2006024775A1 (fr) Piege a ions a aimant permanent longitudinal et spectrometre de masse utilisant un tel aimant
FR2637725A1 (fr) Dispositif d'extraction et d'acceleration des ions limitant la reacceleration des electrons secondaires dans un tube neutronique scelle a haut flux
FR2759491A1 (fr) Cathode froide a emission de champ et son procede de fabrication
FR2641899A1 (fr) Canon a electrons muni d'un dispositif actif produisant un champ magnetique au voisinage de la cathode
FR2468203A1 (fr) Appareil a decharge electrique a cathode creuse
EP0532411B1 (de) Elektronzyklotronresonanz-Ionenquelle mit koaxialer Zuführung elektromagnetischer Wellen
EP0104973A1 (de) Vorrichtung zur Ionisierung eines Materials durch Hochtemperaturheizung
EP0362953A1 (de) Mit einer Ionenquelle mit elektrostatischem Einschluss versehene abgeschmolzene Neutronenröhre
EP0483004B1 (de) Quelle starkgeladener Ionen mit polarisierbarer Probe und mit Elektronzyklotronresonanz
EP2311061B1 (de) Elektronenzyklotronresonanzionengenerator
FR2714966A1 (fr) Jauge à ionisation munie d'une cathode à micropointes.
EP0300932B1 (de) ELektronenquelle
EP0002406B1 (de) Ionenquelle, insbesondere für eine Ionenimplantationseinrichtung
FR2623658A1 (fr) Dispositif fonctionnant avec ionisation par contact pour l'elaboration d'un rayon d'ions acceleres

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): CH DE GB LI

17P Request for examination filed

Effective date: 19880316

17Q First examination report despatched

Effective date: 19891117

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE GB LI

REF Corresponds to:

Ref document number: 3780675

Country of ref document: DE

Date of ref document: 19920903

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19930403

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19930430

Ref country code: CH

Effective date: 19930430

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19930403

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19940101